Patterned magnetic recording medium and method of manufacturing the same

ABSTRACT

Provided are a patterned magnetic recording medium which has an extremely planarized surface and a method of manufacturing the same. The medium includes a patterned magnetic layer including a plurality of magnetic columns that are arranged with a predetermined pitch therebetween; a substrate that supports the patterned magnetic layer; and a boundary layer, which is filled in gaps between the magnetic columns of the patterned magnetic layer. Thus, an air bearing due to stable airflow is created over the magnetic layer, and magnetic recording/reproduction are easily achieved at ultrahigh density.

This application claims the priority of Korean Patent Application No.2003-49550, filed on Jul. 19, 2003, in the Korean Intellectual PropertyOffice, the disclosure of which is incorporated herein in its entiretyby reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a patterned magnetic recording mediumand a method of manufacturing the same, and more particularly, to aplanarized patterned magnetic recording medium and a method ofmanufacturing the same.

2. Description of the Related Art

When a magnetic grain size is reduced to less than a certain criticalvalue, a magnetic recording medium that employs a typical bulk magneticlayer reveals a superparamagnetic effect. The superparamagnetic effectreduces the number of bits per area, i.e., the recording density. Thus,to improve the recording density by suppressing the superparamagneticeffect, there is provided a patterned medium on which magnetic grainsare structurally isolated from one another. U.S. Patent Applications No.2002/0068195 A1 and No. 2002/0154440 A1 disclose such a patternedmedium. In comparison with a conventional magnetic recording mediumusing a bulk magnetic layer, such a patterned medium leads to a muchhigher recording density of approximately 1000 Gbit per inch square ormore.

FIG. 1 is an exploded view of a conventional patterned magneticrecording medium. The patterned magnetic recording medium is in the formof a disk that is rotated by a spindle motor, but FIG. 1 illustratesonly an exploded portion thereof.

Referring to FIG. 1, a soft magnetic under layer 11 is disposed on thesurface of a substrate 10 formed of glass or aluminum or a platter, anda buffer layer 12 is disposed on the soft magnetic under layer 11. Apatterned magnetic layer 13 is then disposed on the buffer layer 12.

The patterned magnetic layer 13 includes a plurality of magnetic columns13 a, which are regularly aligned with a pitch of 0.2 nm and have aheight of approximately several to several tens of nm. Thus, air gapsare formed in spaces between the magnetic columns 13 a.

In such a circumference, if a relative movement between the medium and aslider 14 on which magnetic recording/reading heads are mounted occursas illustrated in FIG. 2, an air bearing 15 is created between theslider 14 and the patterned magnetic layer 13. At this time, air flowsthrough the air gaps between the magnetic columns 13 a below the airbearing 15. Thus, the pressure of the air bearing 15, which is appliedbetween the slider 14 and the patterned magnetic layer 13, is reduceddue to air turbulence.

As the pressure of the air bearing 15 is reduced and becomes unstable,the slider 14 using a swing arm cannot stably swing over the patternedmagnetic layer 13 and, above all, the slider 14 collides with thepatterned magnetic layer 13, thereby causing defects to the magneticlayer 13.

SUMMARY OF THE INVENTION

The present invention provides a patterned magnetic recording mediumwhich can produce a stable air bearing and a method of manufacturing thesame. Thus, a slider can stably fly over a magnetic layer owing to thestable air bearing, and collision of the slider with the magnetic layercan be prevented.

Also, the present invention provides a patterned magnetic recordingmedium in which a boundary layer formed of a nonmagnetic insulator isdisposed between patterned magnetic columns to thereby reduce noiseinterferences between bits comprised in the patterned columns and amethod of manufacturing the same.

According to an aspect of the present invention, there is provided apatterned magnetic recording medium comprising a patterned magneticlayer including a plurality of magnetic columns that are arranged with apredetermined pitch; a substrate, which supports the patterned magneticlayer; and a boundary layer, which is filled in gaps between themagnetic columns of the patterned magnetic layer.

A buffer layer may be disposed between the patterned magnetic layer andthe substrate.

A soft magnetic under layer may be disposed between the buffer layer andthe substrate.

According to another aspect of the present invention, there is provideda method of manufacturing a patterned magnetic recording medium. Themethod includes preparing a substrate; forming a boundary layer on thesubstrate, the boundary layer having wells that are arranged with apredetermined pitch; filling the wells with a magnetic material layer bycoating the magnetic material layer on the boundary layer; andplanarizing the boundary layer and a magnetic layer including magneticcolumns filled in the wells of the boundary layer.

When the substrate is prepared, a soft magnetic under layer and a bufferlayer may be formed on the substrate.

To form the boundary layer, a nonmagnetic material may be coated on thesubstrate to a predetermined thickness, and a boundary layer havingwells may be formed by patterning the nonmagnetic material in apredetermined pattern.

The coating of the magnetic material layer may comprise annealing thecoated magnetic material layer at a predetermined temperature. Thebarrier layer and the magnetic layer may be planarized using plasmaetching.

The boundary layer may be formed of one of silicon oxide (SiO₂) andsilicon oxynitride (Si₃N₄), which are dielectric materials, usingchemical vapor deposition (CVD) or physical vapor deposition (PVD), forexample, plasma-enhanced chemical vapor deposition (PECVD) or plasmasputtering.

Also, the magnetic material layer may be formed of tetracyanoethanide(TCNE)-based magnetic polymer using spin coating or CVD. The magneticmaterial layer may be annealed at a temperature ranging from 100 to 300°C. Thus, the magnetic material layer is reflowed and densified and voidsin the wells are completely removed.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and advantages of the present inventionwill become more apparent by describing in detail exemplary embodimentsthereof with reference to the attached drawings in which:

FIG. 1 is an exploded view of a conventional patterned magneticrecording medium;

FIG. 2 illustrates a relationship between an air bearing that isproduced over the conventional magnetic recording medium of FIG. 1 and aslider;

FIG. 3 is an exploded view of a patterned magnetic recording mediumaccording to the present invention;

FIG. 4 illustrates a relationship between an air bearing that isproduced over the surface of the patterned magnetic recording medium ofFIG. 3 and a slider flying over the patterned magnetic recording medium;and

FIGS. 5A through 5G are cross-sectional views illustrating a method ofmanufacturing the patterned magnetic recording medium of FIG. 3.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will now be described more fully with reference tothe accompanying drawings, in which exemplary embodiments of theinvention are shown.

FIG. 3 is an exploded view of a patterned magnetic recording mediumincluding a planarized magnetic recording layer, according to thepresent invention.

Referring to FIG. 3, a soft magnetic under layer 101 is disposed on asubstrate 100 formed of glass or aluminum or a platter, and a bufferlayer 102 is disposed on the soft magnetic under layer 101. On top ofthe buffer layer 102, a patterned magnetic layer 103 is disposed. Themagnetic layer 103 includes a patterned boundary layer 103 b, which ispatterned in gratings, and patterned magnetic columns 103 a, which arefilled in a plurality of wells formed in the patterned boundary layer103 b.

Since the patterned magnetic layer 103 has no air gaps between themagnetic columns 103 a, air turbulence or pressure reduction due toairflow does not occur. As a result, a stable air bearing 105 isproduced between a slider 104 and the patterned magnetic layer 103, asillustrated in FIG. 4.

This stable air bearing 104 allows the slider 104 to stably fly over themagnetic layer 103 and prevents collision or friction between the slider104 and the magnetic layer 103.

In addition, the boundary layer 103 formed of a nonmagnetic insulator,which is disposed between the magnetic columns 103 a, can reduce noiseinterferences between respective bits comprised in the magnetic columns103 a.

To realize a high data recording density of approximately 1000 Gb/in²,the size of each of the wells formed in the boundary layer 103 b, i.e.,the area of each of the magnetic columns 103 a, should be approximately25 nm, and the thickness of the boundary layer 103 b, i.e., the pitchbetween the wells, should be limited to approximately several nm. Theseconditions can be satisfied using nanolithographic technology.

Hereinafter, a method of manufacturing a patterned magnetic recordingmedium according to an embodiment of the present invention will bedescribed with reference to FIGS. 5A through 5G.

Referring to FIG. 5A, a substrate 100 on which a soft magnetic underlayer 101 and a buffer layer 102 are formed is prepared.

Referring to FIG. 5B, a material layer 103 b for forming a magneticbarrier layer is formed on the buffer layer 102 using plasma-enhancedchemical vapor deposition (PECVD) or sputtering.

Referring to FIG. 5C, a photoresist mask 200 is formed on the materiallayer 103 b for forming the magnetic barrier layer. To realize asubsequent nanometer patterning process, the photoresist mask 200 isformed using a nanolithgraphic technique, such as electronic beamlithography, X-ray lithography, deep ultraviolet (DUV) lithography,extreme ultraviolet (EUV) lithography, or nanoimprinting.

Referring to FIG. 5D, portions of the material layer 103 for forming themagnetic barrier layer, which are not covered by the photoresist mask200, are etched using a reactive ion beam etch (RIE) process. Thus,wells 103 c are formed in the material layer 103 b for forming thebarrier layer, and a desired barrier layer 103 b is obtained. After thebarrier layer 103 b is formed, the photoresist mask 200 is removed bystripping.

Referring to FIG. 5E, a magnetic material layer 103 a formed oftetracyanoethanide (TCNE) is formed to a predetermined thickness on thebarrier layer 103 b. The magnetic material layer 103 a is formed tocompletely fill the wells 103 c and cover the barrier layer 103 b.

Referring to FIG. 5F, the magnetic material layer 103 a is annealed at atemperature of approximately 100 to 300° C. to allow the magneticmaterial layer 103 a to reflow. Thus, the material layer 103 a isdensified, voids are completely removed, and the surface of the materiallayer 103 a is less flexural.

Referring to FIG. 5G, an etchback process, i.e., plasma etching, isperformed on the entire surface of the magnetic material layer 103 a. Asa result, a planarized magnetic layer 103, which includes the barrierlayer 103 b and magnetic columns 103 a that are filled in wells formedin the barrier layer 103 b, is completed as shown in FIG. 5H.

In the present invention, a polymer-based magnetic material is usedinstead of conventionally used metal- or ceramic-based magneticmaterials. Here, magnetic polymer is used not only as a magneticrecording material but also as a material for planarizing a geometricstructure. Accordingly, a desired patterned magnetic recording layer canbe obtained using a process that is no more complicated than a processin the conventional case.

Meanwhile, since magnetic polymer is deposited using spin coating orchemical vapor deposition (CVD), which is processed very slowly, thebarrier layer 103 b with a very fine structure has a good step coveragecharacteristic. Also, the annealing process is performed so that themagnetic material layer 103 a is reflowed and densified and theroughness of its surface is improved. As a result, a planarizedrecording layer with a roughness of 1 nm or less can be obtained. If aplanarization process using an etch process is additionally performed, arecording layer with an extremely low roughness of 1 nm or less can beobtained.

As a stable air bearing is produced on the recording layer, the slidercan fly over the recording layer while maintaining a very constantflying height.

As explained thus far, a recording layer that has a very planarizedsurface and allows a stable air bearing can be achieved. Thus, anultrahigh recording density of 1000 Gb/in² can be ensured. Further, byusing a boundary layer formed of a nonmagnetic insulator, which isdisposed between patterned magnetic columns, noise interferences betweenbits can be reduced.

While the present invention has been particularly shown and describedwith reference to exemplary embodiments thereof, it will be understoodby those of ordinary skill in the art that various changes in form anddetails may be made therein without departing from the spirit and scopeof the present invention as defined by the following claims.

1. A patterned magnetic recording medium comprising: a patternedmagnetic layer including a plurality of magnetic columns that arearranged with a predetermined pitch; a substrate, which supports thepatterned magnetic layer; and a boundary layer, which is filled in gapsbetween the magnetic columns of the patterned magnetic layer.
 2. Themedium of claim 1, further comprising a buffer layer disposed betweenthe patterned magnetic layer and the substrate.
 3. The medium of claim2, further comprising a soft magnetic under layer disposed between thebuffer layer and the substrate.
 4. The medium of claim 1, wherein themagnetic columns are formed of a tetracyanoethanide (TCNE)-basedmaterial.
 5. The medium of claim 1, wherein the boundary layer is formedof one of silicon oxide (SiO₂) and silicon oxynitride (Si₃N₄).
 6. Amethod of manufacturing a patterned magnetic recording medium, themethod comprising: preparing a substrate; forming a boundary layer onthe substrate, the boundary layer having wells that are arranged with apredetermined pitch; filling the wells with a magnetic material layer bycoating the magnetic material layer on the boundary layer; andplanarizing the boundary layer and a magnetic layer including magneticcolumns filled in the wells of the boundary layer.
 7. The method ofclaim 6, wherein the preparing of the substrate comprises forming a softmagnetic under layer and a buffer layer on the substrate.
 8. The methodof claim 6, wherein the forming of the boundary layer comprises: coatinga nonmagnetic material on the substrate to a predetermined thickness;and forming a boundary layer having wells by patterning the nonmagneticmaterial in a predetermined pattern.
 9. The method of claim 6, whereinthe coating of the magnetic material layer comprises annealing thecoated magnetic material layer at a predetermined temperature.
 10. Themethod of claim 7, wherein the coating of the magnetic material layercomprises annealing the coated magnetic material layer at apredetermined temperature.
 11. The method of claim 8, wherein thecoating of the magnetic material layer comprises annealing the coatedmagnetic material layer at a predetermined temperature.
 12. The methodof claim 6, wherein the planarizing of the barrier layer and themagnetic layer is performed using plasma etching.
 13. The method ofclaim 6, wherein the boundary layer is formed of one of silicon oxide(SiO₂) and silicon oxynitride (Si₃N₄), which are dielectric materials.14. The method of claim 8, wherein the boundary layer is formed of oneof silicon oxide (SiO₂) and silicon oxynitride (Si₃N₄), which aredielectric materials.
 15. The method of claim 8, wherein the boundarylayer is formed using one selected from the group consisting of chemicalvapor deposition, plasma-enhanced chemical vapor deposition, andphysical vapor deposition.
 16. The method of claim 6, wherein themagnetic material layer is formed of tetracyanoethanide (TCNE)-basedmagnetic polymer.
 17. The method of claim 16, wherein the magneticmaterial layer is formed using one of spin coating and chemical vapordeposition.
 18. The method of claim 17, further comprising annealing themagnetic material layer at a temperature ranging from 100 to 300° C. toallow the magnetic material layer to reflow.